


Anger Management (W.D. Gaster x Grillby)

by EsperAqua



Category: Undertale (Video Game)
Genre: Anal Sex, Anger, Anger Management, Blow Jobs, College, Fluff and Smut, Gay, Gay Sex, M/M, One Shot, Pre-Accident W. D. Gaster, Rough Sex, Short One Shot, Smut, anger issues
Language: English
Status: Completed
Published: 2016-12-03
Updated: 2016-12-03
Packaged: 2018-09-06 03:20:50
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,330
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8732803
Author URL: https://archiveofourown.org/users/EsperAqua/pseuds/EsperAqua
Summary: Gaster has anger issues, but he knows what will help tease the tension.





	

**Author's Note:**

> This is a very short one shot story that was prompted during a 1 hour writing challenge. It is not meant to be an entire long story, just some quick and hot smut!

“No! No no no! This can't be happening!”

Gaster snarled out in anguish as yet another one of his experiments failed, crumbling before his eyes and turning into dust. He had been so close this time, it was almost completed, it was almost whole! However, despite everything he did to make it work, his experiment failed. They always failed.

He dropped his head into his hands and clutched at his skull, the tips of his boney fingers scratching against the surface. Slowly he got up from his stool and took the failed project into his hands, dumping it forcefully in the trash beside him loudly. The other classmates in the college science lab had begun to stare, but he paid them no mind. Growling lowly he took his materials into his hands and left the practice laboratory dramatically, slamming the door on his way out.

Gaster fumed as he walked off the campus, occasionally summoning bullets to send crashing into the rocky walls that outlined his path. He always had issues with his temper, he knew this, but there was always someone who could bring him back beyond his anger... Someone who could put the world back into perspective and make everything seem alright. He had to go see them, they would make him feel better.

 

Gaster arrived at his destination, a small dive in hotlands named “The Hole in the Wall”. It was appropriately named as it literally consisted of small cave entrance that was naturally carved into the walls hundreds of years before.

Walking up to the bar, Gaster took a seat in his regular spot. It was only moments later that a bartender walked up to him with a smile.

“Ah, hello Gaster, rough day I take it? The usual?”

“You know me so well. Yes, Grillby, the usual would be wonderful.” Gaster smiled back at the tall and striking fire elemental that stood before him. Grillby had begun working at the bar only a year before, but for someone without any formal training he had an amazing knack for making the most delicious mixed drinks. Gaster supposed that was why the owner of the establishment hired him so quickly. Monsters with actual talent were few and far between in the Underground.

Grillby nodded at Gaster's request and poured him a whiskey on the rocks, adding a cherry in for a little bit of flare. He slid the drink over to Gaster with a smile. “So, tell me, what's the problem this time?”

Gaster sighed and rolled his eyes, taking a sip with a hum. “You know, the usual. Failed experiments, frustration, anger... I don't know why I ever signed up for this class. The subject just isn't my forte.”

“What was it again? Creationism or something along those lines?”

“Yeah, _something_ along those lines. I think I should stick to engineering instead, at least that is something I'm good at. It's when I can use my hands and really get in there.”

Grillby snickered and placed his hand over Gaster's. “I know how you can use those hands and really get in somewhere...”

Gaster looked up from his glass and smirked. “Like I said, you know me so well... Your drinks aren't the only reason why I come all the way over here.” He took the cherry out of his drink and licked at it with his long purple tongue.

Grillby ran his other hand over Gaster's cheekbone and tilted his chin up. “I'm well aware of that. I get off work soon, stick around and then maybe I can get _you_ off.”

Gaster purred and traced his finger around the rim of the glass, looking into Grillby's eyes. “That sounds like a wonderful idea.”

 

Gaster and Grillby left the bar together, hand in hand. The two of them had been seeing each other for about a month now and the sexual tension between the two monsters was palpable. They barely got through the door to Gaster's apartment before they were practically tearing off each others' clothing.

As Grillby tossed Gaster's sweater over to the side of the room hastily, he brought his mouth up to Gaster's neck and began sucking on the side of his vertebrae, causing Gaster to moan audibly.

Gaster grabbed at Grillby's hips and pulled him into his body, grinding his body roughly against his. His hands moved to his dress shirt and ripped it open, buttons flying off to the sides. “I need release. I need it right now.”

Grillby laughed deeply and dropped down to his knees, unzipping Gaster's pants, freeing his large purple magic cock from his black slacks. He brought it to his lips, licking away a large bead of pre-cum that had begun to form, then began to kiss the tip of his twitching head. The heat from his mouth instantly caused Gaster to groan and buck instinctively. Grillby smirked and took it all into his mouth, sucking and licking swiftly, roughly, as he knew what his lover liked.

Gaster gripped onto the back of Grillby's head and began to thrust his hips forward sharply, grunting and panting at each thrust. He smirked as he looked down at the flaming man below him, humming in delight as he sucked him off.

It all felt so wonderful, as it always did, but this time it just wasn't enough. His lust for Grillby was insatiable. Gaster growled as he withdrew his cock from Grillby's mouth and stepped away from him.

“W-what's wrong? Did it not feel good?”

“It felt incredible, but.... Get on your hands and knees, right now. I need to fuck you.”

Grillby's face flushed white hot and he nodded, spinning around into Gaster's demanded position.

Gaster got down onto his knees behind Grillby and pulled his brown slacks down forcefully, exposing Grillby's ass to him. He hummed in delight as he slapped the side of his hips, marveling at the white hand shaped imprint he left behind temporarily. He took his wet cock in his hand and lined it up with Grillby's tight opening.

“Don't worry about being being gentle, I know you like to be rough.” Grillby moaned out as he clutched at the floor, bracing for impact.

Gaster growled and smirked, grabbing at Grillby's hips. “You know me so _well_...” Gaster slid his throbbing cock into Grillby's ass roughly, laughing deeply as his partner yelled out in a combination of pain and pleasure. He began to buck into him swiftly, moaning at the tightness and warmth of Grillby's insides. As he continued to thrust Gaster bent forward and grabbed Grillby's cock in his boney magic laced hand, stroking it to the rhythm of his thrusts.

Grillby moaned and panted roughly beneath Gaster as his backside was pummeled by the strong monster in back of him. He could feel himself come to climax quickly and started bucking his hips to match Gaster's thrusting.

“I-I'm going to cum. Cum with me.” Gaster growled, his thrusts becoming erratic. Suddenly, he felt the rush he had been seeking and his cock began to spasm inside Grillby's tight opening. Spurts of generous cum erupted from the tip of his twitching member, filling him up and spilling down onto the floor below him.

Grillby gasped out and arched his back up, moaning out loudly as he came. Ribbons of lava like cum shot out from him in swift spurts, coating the ground.

After a minute of soft pumping to make sure his partner was milked thoroughly, Gaster hummed as he pulled out, bending down to kiss Grillby's back tenderly. “Thank you, you always know how to make me feel better.”

Grillby flipped over into a sitting position against the wall and smiled, taking Gaster into his arms, his back pressing against his chest. “Indeed I do, and I could say the same about you...”

Gaster smiled and sighed out happily, running his hands up through his lover’s fiery hair... Grillby certainly knew how to make everything right in the world.

 


End file.
